I. Field of the Invention
The present invention relates generally to computer modeling and management of systems and, more particularly, to computer simulation techniques with real-time system monitoring and prediction of electrical system performance.
II. Background of the Invention
Computer models of complex systems enable improved system design, development, and implementation through techniques for off-line simulation of the system operation. That is, system models can be created that computers can “operate” in a virtual environment to determine design parameters. All manner of systems can be modeled, designed, and operated in this way, including machinery, factories, electrical power and distribution systems, processing plants, devices, chemical processes, biological systems, and the like. Such simulation techniques have resulted in reduced development costs and superior operation.
Design and production processes have benefited greatly from such computer simulation techniques, and such techniques are relatively well developed, but such techniques have not been applied in real-time, e.g., for real-time operational monitoring and management. In addition, predictive failure analysis techniques do not generally use real-time data that reflect actual system operation. Greater efforts at real-time operational monitoring and management would provide more accurate and timely suggestions for operational decisions, and such techniques applied to failure analysis would provide improved predictions of system problems before they occur. With such improved techniques, operational costs could be greatly reduced.
For example, mission critical electrical systems, e.g., for data centers or nuclear power facilities, must be designed to ensure that power is always available. Thus, the systems must be as failure proof as possible, and many layers of redundancy must be designed in to ensure that there is always a backup in case of a failure. It will be understood that such systems are highly complex, a complexity made even greater as a result of the required redundancy. Computer design and modeling programs allow for the design of such systems by allowing a designer to model the system and simulate its operation. Thus, the designer can ensure that the system will operate as intended before the facility is constructed.
Once the facility is constructed, however, the design is typically only referred to when there is a failure. In other words, once there is failure, the system design is used to trace the failure and take corrective action; however, because such design are so complex, and there are many interdependencies, it can be extremely difficult and time consuming to track the failure and all its dependencies and then take corrective action that doesn't result in other system disturbances.
Moreover, changing or upgrading the system can similarly be time consuming and expensive, requiring an expert to model the potential change, e.g., using the design and modeling program. Unfortunately, system interdependencies can be difficult to simulate, making even minor changes risky.
For example, no reliable means exists for predicting in real-time the potential energy released for an alternating current (AC) or direct current (DC) arc flash event is available. Moreover, no real-time system exists that can predict the required personal protective equipment (PPE) or safe distance boundaries (i.e., protection boundaries) for technicians working around components of the electrical system that are susceptible to arc flash events as required by NFPA 70E and IEEE1584. All current approaches are based on highly specialized static simulations models that are rigid and non-reflective of the facility's operational status at the time that the technician is conducting the repairs on the electrical equipment. As such, the PPE level required for the repair, or the safe distance boundaries around the equipment may change based on the actual operational status of the facility and the alignment of the power distribution system at the time that the repairs are performed.
Conventional static arc flash simulation systems use a rigid simulation model that does not take the actual power system alignment and aging effects into consideration when computing predictions about the operational performance of an electrical system. These systems rely on exhaustive studies to be performed off-line by a power system engineer who must manually modify a simulation model so that it is reflective of the proposed facility operation conditions before conducting the static simulation or the series of static simulations. Therefore, they cannot readily adjust to the many daily changes to the electrical system that occur at a facility (e.g., motors and pumps may be put on-line or pulled off-line, utility electrical feeds may have changed, etc.) nor accurately predict the various aspects (i.e., the quantity of energy released, the required level of worker PPE, the safe protection boundaries around components of the electrical system, etc.) related to an arc flash event occurring on the electrical system.
Moreover, real-time arc flash simulations are typically performed by manually modifying the simulation model of the electrical power system such that the automatic transfer switch (ATS) of the bypass branch of the uninterrupted power supply (UPS) component is set to a bypass position. After, arc flash analyses and/or simulations are performed using the modified simulation model. One challenge with this approach is that while the arc flash analysis and/or simulation is being performed, the simulation model is not identical to the system being modeled. The arc flash analysis typically lasts for several seconds. If during that time another analysis (e.g., power flow, etc.) needs to be performed, the simulation model will not be indicative of the true state of the electrical power system (as it will have the ATS set to a bypass position), resulting in misleading data to be generated from the analyses and/or simulations performed using the modified simulation model.